Cleisostoma hainanense M.Z.Huang, D.K.Liu & G.S.Yang, 2020

Huang, Ming-Zhong, Liu, Ding-Kun, Yin, Jun-Mei & Yang, Guang-Sui, 2020, Cleisostoma hainanense, a new species (Orchidaceae: Epidendroideae) from Hainan, China: evidence from morphological and DNA analyses, Phytotaxa 428 (3), pp. 263-270 : 269

Cleisostoma hainanense M.Z.Huang, D.K.Liu & G.S.Yang , sp. nov. (海#ḃfi兰; Fig. 2, 3)

Type:— China. Hainan: Lingshui City, Mount Diaoluoshan, tree trunks, 900 m, 16 March 2011, Huang 13070201 (holotype & paratype: ATCH!).

This new species is similar to C. paniculatum (Ker Gawler) Garay , but differs in smaller plant; tauren-shaped mid-lobe with truncated tip; conical spur with inconspicuous septum; and arch-shaped back wall callus.

Epiphytic herb. Stem up to 30 cm, ca. 0.5 cm in diameter, erect, producing numerous elongate roots ca. 2 mm in diameter. Leaf-blade leathery, straight or slightly recurved, narrowly oblong, 6–13 × 0.7–0.9 cm, ligulate unequally bilobed, sometimes mucronate in sinus; sheath 1–2 cm long. Inflorescences axillary, up to 20 cm, 2–3 branched, many flowered; floral bracts ovate-triangular, ca. 1.6 × 1.3 mm. Flowers ca. 0.8 mm in diameter; sepals and petals brown, margins and midvein yellowish green, lip creamy yellow; pedicel and ovary ca. 5 mm. Dorsal sepal elliptic, concave, 3.1–3.5 × 2.0– 2.2 mm, obtuse; lateral sepals obliquely oblong, 3.8–4.0 × 2.3–2.5 mm, base adnate to column foot. Petals sub-oblong, ca. 3.4 × 1.4 mm; lip with lateral lobes erect, deltoid, ca. 1.6 × 1.0 mm, at the proximal horizontal edge a rather conspicuous flap adnate to column foot, apex obtuse, proximal margin with a thickened-callose; mid-lobe fleshy, tauren-shaped, at a right angle to the spur, ca. 2.0 mm long, apex truncate, with 2 basal backward subulate lobules, adaxially with a divergent ridge connected with tip and two subulate lobules, and then lowering into spur; spur straight, conical, ca. 2.0 mm, apex obtuse, interior inconspicuously septate, with a back wall callus; callus arc-shaped, slightly bilobed, top smooth and the remaining densely papillate-hairy. Column stout; anther cap truncate, incised; stipe short, broad, geniculate-folded at base; viscidium saddle-shaped, large.

Etymology: —The specific epithet refers to the locality of Hainan Province where this new species has been found.

Phenology: —Flowering from May to July.

Distribution: —Known thus far only from Mount Wuzhishan and Mount Diaoluoshan on Hainan Province, China.

Habitat: —Epiphyte on tree trunks in broad-leaved evergreen forests.

Conservation status: —We found only several populations around 800–1300 m. It is an endemic species, known only from Hainan Province, China.